import math

t = input("Введите текст: ")
w = t.split()
x = ''

for i in w:
  if i == "one":
    x += "1"
  if i == "two":
    x += "2"
  if i == "three":
    x += "3"
  if i == "four":
    x += "4"
  if i == "five":
    x += "5"
  if i == "six":
    x += "6"
  if i == "seven":
    x += "7"
  if i == "eight":
    x += "8"
  if i == "nine":
    x += "9"
  if i == "zero":
    x += "0"

def has_digits(input_string):
  return any(char.isdigit() for char in input_string)


def is_prime(num):
  if num <= 1:
      return False
  for i in range(2, int(math.sqrt(num)) + 1):
      if num % i == 0:
          return False
  return True
  
def find_nearest_prime(num):
  lower = num - 1
  upper = num + 1
  
  while not is_prime(lower) and not is_prime(upper):
    lower -= 1
    upper += 1
  
  if abs(lower - num) <= abs(upper - num):
    return lower
  else:
    return upper

if has_digits(x):
  print("Wrong input")
else:
  num = int(x)
  nearest_prime = find_nearest_prime(num)
  print(nearest_prime)